Sable Palm Tree Problems

Identification

• All palm species are susceptible to the serious ganoderma butt rot disease caused by the Ganoderma zonatum fungus. Favorable conditions that contribute to the spread of the disease are not known. The fungus spreads to trees with spores. Texas phoenix palm decline or TPPD is another likely disease of the Sabal palm. The bacterial disorder is transmitted to tree by plant hoppers and other sap feeding pests.

Damage

• The ganoderma fungus is a soilborne, white rot pathogen that infests woody, water-conducting tissues of the tree. The fungus enters the tree through the roots but does not affect the roots. Tree areas close to the soil line are the first to be affected, and the fungus eventually rots the entire 4 to 5 feet of the lower trunk. The bacterial TPPD is referred to as a phytoplasma that infests the phloem or water-conducting tissues in infected palms. The Sabal palm is among the susceptible hosts of the disease.

Symptoms

• Early symptoms of ganoderma butt rot include slowly declining tree health and yellowing, wilting foliage. An outstanding symptom is the development of hard conks, small shelf or bracketlike structures, on the tree side. The conks are glossy, reddish brown in color with white undersides. TPPD causes sudden fruit drop in mature trees within a few days. This is followed by the death of flowers. These symptoms occur if palms are mature enough to produce fruit and during flowering season. Other trees show the discoloration of the mature foliage into shades of yellow, reddish brown to gray starting from leaf tips. There is extensive root decay in infected trees.

Control

• There are no chemical control options for ganoderma butt rot once a tree has been infected. Monitor any palm stumps close to healthy trees as the fungus rapidly infect stumps and becomes a source for spreading spores. Remove the palm immediately after the appearance of conks to reduce chances of disease infection. Avoid planting other palms in the same area as the fungus persists for extended periods in the soil. Injecting trees with a preventative antibiotic is the only method to avoid TPPD in susceptible palm species. There is no cure once trees are infected. Remove sick trees promptly to minimize spread of disease.